Flashcards in Types Of CT Deck (15):
What are the 2 types of CT proper? Which is the most abundant?
- Loose CT (most abundant)
- Dense CT
Compare the structure of loose and dense CT proper.
Cell no. :
~ loose - many
~ dense - few (nearly all fibroblasts)
~ loose - sparse collagen fibres
~ dense - many collagen fibres
~ loose - abundant (viscous, gel-like consistency - important role in transport, diffusion)
~ dense - little
Where is loose connective tissue primarily located?
- Beneath epithelia (e.g. Superficial layer of dermis and submucosa of colon) - facilitate diffusion.
- Around small blood vessels
- Associated with epithelium of glands
~ sites where pathogens can be challenged and destroyed by the cells of the immune system
What are the 3 types of loose CT?
1. Areolar: most common form, beneath all epithelial layers.
2. Adipose: limited extracellular space but many adipocytes.
3. Reticular: dominated by reticular fibres, e.g. In glands.
What is the function of loose connective tissue?
Allows free movement with minimal resistance.
What are the 2 types of dense CT?
Compare regular and irregular dense CT.
Collagen fibres are arranged:
- regular - densely packed in parallel bundles (fibroblasts between bundles)
- irregular - densely packed in bundles oriented in various directions (fibroblasts between bundles)
- regular - in a single direction
- irregular - in multiple directions
- regular - tendons, ligaments and aponeuroses
- irregular - submucosa of intestine and deep layers of dermis
How are collagen bundles in regular dense CT arranged in tendons and ligaments?
- Tendons (bone to muscle): lie in a parallel, densely packed formation in line with the tensile force exerted by the muscle.
- Ligaments (bone to bone): densely packed in parallel arrangement but undulate, and are arranged in fascicles, separated by loose CT.
What is an aponeurosis?
Flat sheet of regular CT with bundles of fibres in one layer arranged at 90 degree angle to those in adjacent layer.
E.g. Lumbar aponeurosis or in abdominal wall.
What is the role of adipose tissue?
- Fat storage (fuel reserve)
- Thermal insulation
- Shock absorption
What are the 2 types of adipocyte tissue?
White fat (most adipose tissue)
What is the difference between white and brown adipocyte tissue?
- uniocular cells - almost entirely filled by a single fat droplet
- cytoplasm displaced to cell rim and nucleus to one side
- multiocular cells - contain many lipid droplets
- central nucleus
Why do uniocular adipose cells appear empty in typical H and E stained, wax-embedded preparations?
Toluene and xylene used in tissue preparation have dissolved away the lipid.
Where is brown adipose tissue found?
- Close to scapula, sternum and axillae, esp. in newborn.
- Upper chest and neck of adults.